1. Field of the Invention
A supply system for feeding a fluid to a vessel is used, in particular, for the later stabilization of substances which are usually stored in vessels or storage tanks and which have a considerable tendency toward undesirable chemical reactions, for example premature polymerization, or other physical reactions, for example crystallization.
2. Discussion of the Background
It is known that certain substances or combinations of substances, in solid or dissolved form, are suitable for restabilizing polymerizable substances which react at an undesirable time. These substances can be introduced into the stored material in a conventional manner and can then be mixed with the contents of the tank using the pump which is customarily provided for filling and emptying the storage tank device. A drawback of this is that pumps themselves may form the starting point for premature polymerization, resulting in the pump becoming blocked. Therefore, if required, the mixing work can no longer be carried out. A further drawback is the need for an external power source for driving the pump which, in an emergency or by chance, may be unavailable, making it impossible to introduce stabilizing liquid.
Therefore, in order to be independent of external power sources, a mixing method which involves blowing in gases is also used. A drawback of this method is that additional internals are required in or on the tank. Generally, such internals have to be secured fixedly to the tank, in order not to be damaged or torn off during normal operation. In order to be effective, i.e. to achieve intimate mixing, internals for injecting gases are usually situated in the vicinity of the bottom of the tank. When these internals are not in use, the reactive substance may penetrate into the internals, where it will generally polymerize owing to the low level of exchange of materials, thus making the gas feed unusable when it is required. For this reason, a slight flow of air is often fed through such lines in order to keep them clear. However, an air flow of this nature also requires the apparatus to be monitored, in order to prevent the liquid stored in the tank from rising back up and to keep the line open. Such designs have proven expensive if they are to fulfill their role reliably.
EP-B-0,064,628 describes a device for emergency shortstopping of polymerization reactions in a closed reaction vessel by adding inhibitor solution. The inhibitor solution is added in the lower part of the vessel via a connection flange which is closed off by a rupture disk. An angled-off riser pipe leading to an upper flange, to which a compressed-gas line is connected, is arranged on this connection flange. The riser pipe is filled with an inhibitor solution which, when required, is forced into the vessel at high pressure by a compressed gas. The compressed gas comes from a compressed-gas cylinder which is connected to the riser pipe via the compressed-gas line.
Due to the immediate proximity of the inhibitor solution to the vessel, the inhibitor solution itself may, particularly in dangerous situations, already have been damaged before it is fed into the vessel, so that it is no longer able to fulfill its actual role. In addition, there is a risk, with the known rupture disk arrangement, of the rupture disk breaking prematurely, making the monomer stored in the tank unusable. The resultant contamination of the storage device then requires lengthy cleaning work owing to the high strength of the inhibitor.
Furthermore, checking the inhibitor solution inside the riser pipe is a complex operation, since this requires the riser pipe to be emptied and refilled. Particularly if there are a plurality of vessels, this represents a considerable drawback. Finally, there is also a risk of the inhibitor solution icing over if the temperatures fall excessively.
The problem on which the invention is based therefore consists in providing a supply system for feeding a fluid to a vessel which is provided with a feedline, which system has a reliable and simple structure and only requires a low level of investment.
According to the invention, the reservoir and the compressed-air store are arranged in immediate proximity to one another, and the reservoir can, when required, be brought into communication with the feedline via a connection piece.
This supply system can be attached to or removed from the vessel at any time. As a result, its correct operation can be tested easily periodically. Due to the structure of the supply system, it can be used on vessels of very different volumes without changing its structural dimensions.
In the supply system according to the invention, liquid or gaseous substances are introduced into the material and the substances are at the same time mixed with the material. The high-pressure fluid can be introduced into the vessel for the purpose of stabilizing the substances inside the vessel and may be a mixture of a gas and a liquid.